Can you recommend open source device that you have to solder and assemble yourself?

I'm getting started with PCB design and SMT soldering. My target goal is to be able to create a device using some microcontroller like ESP32 with power supply and periphery devices on a single PCB, however I feel a bit overwhelmed and don't know where to start.

I would like to build some device that was designed and tested by someone else to understand better what is going on and learning by doing. Ideally I would like to order PCB from something like JLCPB and get components to assemble it. Do you have any suggestions?

P.S. I used a practice board for SMT soldering, but it's no fun, especially because you cannot test that it works.

P.P.S. I also saw this option https://www.roboticworx.io/p/build-custom-esp32-boards-from-scratch which looks good, and I might try to do that if I don't find a better option.